Classes to perform analysis based on the smalldata files. Can also be sued to analyze xtc files directly. Is at the core of the cube.

2022.02.25: Misc notes while making these classes LCLS-II compatible (t be re-organized)

self._fields:

self.XrData: xArray data loaded from h5 files. Hold a bunch of default detectors (1d dets, IPMS, ....) upon creation. Gets bigger as we add more variable manually.